Messaging is an expanding part of wireless transmission systems. The prior art, however, fails to make efficient use of scarce radio resources with respect to the transmission of messages.
In the case of general broadcasts, messages are transmitted at a specific time, on a specific channel, with a specific channelization code. Broadcast messages are only retransmitted if there is a problem with the robustness of delivery or timing (i.e., devices typically want to receive a message while being in the right place at the right time). Broadcast messages, however, are often transmitted over large geographical regions and therefore encompass a large number of cells. For this reason, broadcasting messages is only efficient where there will be a large number of users receiving the message.
Multicasting, where messages are sent to a predetermined number of users, involves limited receivers and selective transmissions to each of the targeted receivers. In contrast to a broadcast message which is transmitted over large geographical regions, with multicasting, multiple instances of the same data (i.e., message) are transmitted, but only to the devices of the target group. Despite being more efficient than broadcasting, transmitting multiple instances of the same message is not an efficient use of radio resources. That is, with prior art multicast transmissions, messages and their associated pointers have a one-to-one correspondence which leads to multiple transmissions of the same message.
Another approach is to assign a group identifier to a number of devices. The group identifier reduces one-to-one correspondence between messages and pointers and allows a single instance of a message to be received by each device having the assigned identifier. The group identifier approach, however, is efficient only where there is prior knowledge of the devices that should form the group and the group identifier is expected to be used a number of times over a period of time. Moreover, since the group identifier must be established in the devices via offline or online programming, it is not an efficient means of ad hoc (ad hoc with respect to at least the wireless network) message delivery. That is, a group page from an email source may indeed be a repeating group, but the RF network will not have a priori knowledge of the repeating group.
Accordingly, a method and system is needed wherein a single message instance may be used for multiple recipients of the same message.